PARIS (AP) – A former U.S. ambassador to the United Nations was among the hundreds of people held inside Notre Dame Cathedral after a hammer-wielding man attacked police and was shot by an officer.

Ambassador Nancy Soderberg said she was admiring the church’s stained glass windows on Tuesday when she heard an announcement in French urging visitors to stay calm as police dealt with an incident outside.

Soderberg told The Associated Press that those inside got nervous when they were told soon after that the cathedral’s doors were closing and everyone had to stay there.

She says the group stayed calm and orderly throughout despite not knowing what was happening, though “everyone was very quiet and very scared” when police came in to check the cathedral’s pews row by row.

Soderberg tweeted a photo from inside the Notre Dame showing those locked inside putting their arms in the air as instructed by police.

Paris is under high security after a string of Islamic extremist attacks in recent years.